In a thermal ink jet printing system, ink is ejected as ink droplets from a print head as a result of rapid volumetric expansion of the ink after the application of thermal energy to the ink. A heater (e.g., resistor) in the print head can be rapidly heated to supply the thermal energy to ink that is in contact with the resistor. Heating the ink to at least its boiling point will create bubbles in the ink. The bubbles experience a rapid volumetric increase forcing a droplet to be ejected from a print head nozzle. The ink may include materials that over time may bond to and build up on the heater surface. This build up may be referred to as kogation. Kogation can reduce the efficiency and useful life of a print head by affecting the thermal transfer properties of the heater surface. Thus, various approaches have been taken to mitigate the effects of kogation.
One approach has been to craft designer inks that contain various materials designed to limit kogation. Some designer inks may be crafted to be so pure that they do not provide residual materials from which kogation may form. However, some inks (e.g., high pH inks) may react with other materials (e.g., silicates) in a print head and cause materials (e.g., silicates) to enter the ink. These silicates may be available for kogation formation on a heater like a resistor. The silicates may be produced when the high pH ink reacts with materials including, for example, a silicon die, a glass-reinforced print head body, and so on.